Chapter 2: Scientific Notation

# x 10 n
• # = greater than or equal to 1 and less than 10.
• n = any number …-2,-1,0,1,2…

Scientific Notation
.00000775 m
20 700 000 000 000 000 000 m

Scientific Notation and
Significant Digits
• When a measurement is expressed in scientific notation all the digits in the number are significant however the 10 n is not a part of the significant digits in that it only tells use how to move the decimal point.
3.60 x 10 25 mg

Scientific Notation and
Significant Digits
• Scientific Notation eliminates the need to use a bar over the zero to make the zero significant.

Scientific Notation
.00000775 m
20 700 000 000 000 000 000 m

Scientific Notation
7.75 x 10 -6 m
2.07 x 10 19 m

Scientific Notation
7.75 x 10 -6 m
2.07 x 10 19 m
Now multiply them together

• (7.75 x 10 -6 m) x (2.07 x 10 19 m) =
1.60425 x 10 14

• (7.75 x 10 -6 m) x (2.07 x 10 19 m) =
1.60425 x 10 14
1.60 x 10 14 m 2

Write the number in scientific notation.
There are 802 000 000 000 000 000 000 000 copper atoms in this sample of copper sulfate.

8.02 x 10 23 Cu atoms
There are 802 000 000 000 000 000 000 000 copper atoms in this sample of copper sulfate.

Write the number in scientific notation.
The mass of a proton is
0.000 000 000 000 000 000 000 001 672 67g

1.67267 x 10 -24 g
The mass of a proton is
0.000 000 000 000 000 000 000 001 672 67g

Practice Problem
• 8.02 x 10 23 copper atoms

Practice Problem
• 8.02 x 10 23 copper atoms
• Each copper atom contains 29 protons

Practice Problem
• 8.02 x 10 23 copper atoms
• Each copper atom contains 29 protons
• Mass of a proton is 1.67267 x 10 -24 grams

Practice Problem
• 8.02 x 10 23 copper atoms.
• Each copper atom contains 29 protons
• Mass of a proton is 1.67267 x 10 -24 grams
• What is the mass of all of copper’s protons in the sample?

Practice Problem
• 8.02 x 10 23 copper atoms.
• Each copper atom contains 29 protons
• Mass of a proton is 1.67267 x 10 -24 grams
• What is the mass of all of copper’s protons in the sample?
• (8.02 x 10 23 )(29)(1.67267 x 10 -24 g)

Practice Problem
• 8.02 x 10 23 copper atoms.
• Each copper atom contains 29 protons
• Mass of a proton is 1.67267 x 10 -24 grams
• What is the mass of all of copper’s protons in the sample?
• (8.02 x 10 23 )(29)(1.67267 x 10 -24 g)
= 38.90295886g

Practice Problem
• 8.02 x 10 23 copper atoms.
• Each copper atom contains 29 protons
• Mass of a proton is 1.67267 x 10 -24 grams
• What is the mass of all of copper’s protons in the sample?
• (8.02 x 10 23 )(29)(1.67267 x 10 -24 g)
= 38.90295886g = 38.9g

Homework

Worksheet: Significant Digits and
Rounding (due tomorrow).

Worksheet: Scientific Notation (due in two days).